• Journal of Sensor Science and Technology
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• v.30 no.2
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• pp.119-124
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• 2021

Isolation and separation of biological nanoparticles, such as cells and extracellular vesicles, are important techniques for their characterization. Dielectrophoresis (DEP) based on microfluidic chips is an effective method to isolate and separate the nanoparticles. However, the electrodes of the DEP chips are electrolyzed by the electrical signals applied to the nanoparticles. Thus, the isolation/separation efficiency of the nanoparticles is reduced considerably. Through this study, we developed a microfluidic DEP chip for reliable isolation/ separation of nanoparticles and developed a passivation technique for the protection of the DEP chip electrodes. The electrode passivation process was designed using a hydrogel and the stability of the hydrogel passivation layer was verified. The fabricated DEP chip and the proposed passivation technique were used for the collection and dispersion of the fluorescent polystyrene nanoparticles. The proposed chip and the technique for isolation and separation of nanoparticles can be leveraged in various bioelectronic applications.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.25-28
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• 1989

This paper is to study a modified hysteresis band current control technique for keeping the fixed switching frequency. The control technique is applied to an brushless DC motor(BLDCM). This paper gives an analysis of the modified hysteresis band with isolated neutral case and the PI controller with current limiter in forward loop; their characteristics are studied by simulation. The proposed control technique is implemented by using a microprocessor-based system.

• Structural Engineering and Mechanics
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• v.9 no.3
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• pp.215-226
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• 2000

Computational procedure within the framework of return mapping technique has been presented to integrate the constitutive behavior of a concrete model. Developed by Ohtani and Chen, this concrete model is based on multiple hardening concept, and is rate-independent and associative. Consistent tangent operator suitable for finite element analysis is derived to preserve the rate of convergence. Accuracy of the integration technique is verified and compared with available experimental data. Computational efficiency is demonstrated by comparing with results based on elasto-plastic tangent.

• Journal of Ocean Engineering and Technology
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• v.16 no.2
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• pp.10-20
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• 2002

본 논문에서는 바다의 자유표면에서 생성되는 항력에 대한 물리적 특성에 대한 연구가 기술되었다. 2차원 파장(Wave Field) 매개변수해석기법(Parametric Analyzing Technique)을 근거로 한 파경계층(Wave Boundary Layer : WBL)의 1차원 모델로서 항력계산과 파경계층의 특성을 추정하였으며 이론의 간략화(Simplifying)에 대한 연구에 주력하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.8
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• pp.1437-1443
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• 2000

This paper considers a channel estimation technique in a wireless local area network (WLAN) system with complementary code keying (CCK) signaling over multipath fading channels. This scheme uses the maximum correlator output of RAKE receiver for the extraction of the channel parameters. The performance of the proposed detection technique is compared with that of a noncoherent detection technique, and a significant improvement of performance is observed in terms of the bit error probability.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.266-269
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• 2012

This paper introduces a signal processing technique for discrimination of ballistic missile's warhead. An interceptor missile to destroy the enemy's ballistic missile requires an information on the location of missile's warhead. In order to detect and locate the missile's warhead, a seeker radar in the interceptor missile makes use of chirp waveform to generate high resolution range profiles(HRRPs). We applied one of the well known spectral estimation technique called ESPRIT (Estimation of Signal Parameters by Rotational Invariance Technique) to these HRRPs to estimate scattering centers on the target. Using the information on the one-dimensional(1-D) scattering centers, we can find the location of the warhead by estimating the length of the missile, Simulation results show that the proposed signal processing technique is efficient in discriminating the warhead of an ballistic missile.

• Journal of Information Processing Systems
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• v.2 no.1
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• pp.1-5
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• 2006

Finding a valid timing constraint is one of the most important issues in the real-time monitoring area. To get the valid timing constraint, a developer executes a real-time process and changes the constraint on a regular basis. This is an exhaustive and time-consuming process. To improve this approach, we propose a timing constraint search technique. This technique uses two load models and one condition proposed in this paper to support the developer in determining the valid timing constraint range in an easy and systematic manner.

• Structural Engineering and Mechanics
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• v.14 no.5
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• pp.543-563
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• 2002

The use of the epoxy pressure injection technique to rehabilitate reinforced concrete beam-column joints damaged by strong earthquakes is investigated experimentally and analytically. Two one-half-scale exterior beam-column joint specimens were exposed to reverse cyclic loading similar to that generated from strong earthquake ground motion, resulting in damage. Both specimens were typical of new structures and incorporated full seismic details in current building codes. Thus the first specimen was designed according to Eurocode 2 and Eurocode 8 and the second specimen was designed according to ACI-318 (1995) and ACI-ASCE Committee 352 (1985). The specimens were then repaired with an epoxy pressure injection technique. The repaired specimens were subjected to the same displacement history as that imposed on the original specimens. The results indicate that the epoxy pressure injection technique was effective in restoring the strength, stiffness and energy dissipation capacity of specimens representing a modem design.

• Journal of electromagnetic engineering and science
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• v.7 no.1
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• pp.1-6
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• 2007

Recently, Mc(Multi-code) modulation/demodulation(modem) technique has been explored for high speed data transmission in wireless environment. The conventional Mc modem generates some side effects such as allocating Walsh codes, which motivates to propose a novel Mc modem method with sub-code. Our proposed system should expanded the size of sub-code to provide high-rate data transmission, which also affect adversely to the performance of the system with high PAPR(Peak to Average Power Ratio). Thus, in this paper, we propose a novel pre-coded Multi-Dimensional HCOC(High Capacity Orthogonal Code) Mc modem technique to reduce the high PAPR, which enables the performance improvement. This proposed system can be easily designed by concatenating HCOC Mc modem with the generic Mc modem. The pre-coding technique that is used in this paper is CAC(Constant Amplitude Coding), that helps the system maintain the constant transmission power and reduce the maximum transmission power.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.3
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• pp.285-291
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• 2008

We have experimentally investigated the cyclic deformation in copper using ultrasonic nonlinearity. The observation and characterization of dislocation substructure have been conducted using transmission electron microscope and electron backscattered diffraction technique. The ultrasonic nonlinearity (${\beta}/{\beta}_0$) was measured by the harmonic generation technique after various fatigue cycles. The microstructural effect on the nonlinearity was discussed regarding the extent of dislocation substructures evolved from low cycle fatigue. The ultrasonic nonlinearity of copper monotonically increased with the fatigue cycles due to the evolution of dislocation cell substructures.